The mechanism of pentose phosphate conversion to hexose monophosphate. I. With a liver enzyme preparation.
The mechanism of pentose phosphate conversion to hexose monophosphate. I. With a liver enzyme preparation.
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磷酸戊糖转化为单磷酸己糖的机制。
DOI：
10.1016/s0021-9258(18)71280-5
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发表时间：
1954
期刊：
影响因子：
--
通讯作者：
P. Z. Smyrniotis
中科院分区：
文献类型：
--
作者：
B. Horecker;M. Gibbs;H. Klenow;P. Z. Smyrniotis
方法和材料-除非另有说明，所用的方法和材料如先前的论文中所述（14）。从给予NaHCY 403后从大鼠肝脏分离的3，4-标记糖原制备戊糖磷酸-2，3-Cl 4（19）。同位素糖原通过磷酸化酶（20）和磷酸葡萄糖变位酶（21）的作用转化为葡萄糖-6-磷酸。产物用溴氧化成6-磷酸葡萄糖酸盐（22），磷酸葡萄糖酸盐酶促转化成核酮糖-5-磷酸和核糖-5-磷酸（23）。以钡盐形式分离的戊糖磷酸混合物含有约80%的戊糖为核酮糖-5-磷酸，约20%的戊糖为核糖磷酸，核糖-5-磷酸-1-C4是从国家标准局的HS Isbell博士那里获得的核糖-1-Cl 4制备的。为此目的，通过在核糖培养基上富集培养，从土壤中分离的产气荚膜杆菌2菌株的无细胞提取物中制备不含转酮醇酶的核糖激酶。培养基含有0.15%的K2 HP 〇 4、0.05%的KH 2 P 〇 4、0.02%的MgS 〇 4。7 H20、0.1%的（NH 4）2S 〇 4和0.1%的正核糖。在37 ℃下24小时后，在Sharples超离心机中收获细胞。大约，2克。将从1升培养基中获得的10 g细胞（湿重）在研钵中以0 ″用6 gm研磨5分钟。的氧化铝，并将糊状物用15 ml. 0.05 M 2-氨基-2-（羟甲基）-1，3-丙二醇缓冲液，pH 7.5（Tris缓冲液）。将通过在15，000 X g下离心30分钟获得的澄清提取物（12 ml.）用2.4 ml. 1.0%硫酸鱼精蛋白（salmine，Lilly）溶液。通过离心收集形成的沉淀物，并在Potter-Elvehjem均化器（24）中用6.0ml.的0.05M K2 HP 04。的
MethodsMaterials-Unless otherwise specified, the methods and materials employed were as described in a previous paper (14). Pentose phosphate-2, 3-Cl4 was prepared from 3, 4-labeled glycogen isolated from rat liver after administration of NaHCY403 (19). The isotopic glycogen was converted to glucose-6-phosphate by the action of phosphorylase (20) and phosphoglucomutase(21). The product was oxidized to 6-phosphogluconate with bromine (22) and the phosphogluconate converted enzymatically to ribulose-5-phosphate and ribose-5-phosphate(23).’The pentose phosphate mixture, isolated as the barium salt, contained about 80 per cent of the pentose as ribulose-5-phosphate and about 20 per cent as ribosed-phosphate.Ribose-5-phosphate-l-C4 was prepared from ribose-l-Cl4 obtained from Dr. HS Isbell of the National Bureau of Standards. For this purpose, ribokinase, free of transketolase, was prepared from cell-free extracts of a strain of Aerobacter aerogenes2 isolated from soil by enrichment culture on a ribose medium. The culture medium contained 0.15 per cent of K2HP04, 0.05 per cent of KH2P04, 0.02 per cent of MgS04. 7H20, 0.1 per cent of (NH4) 2S04, and 0.1 per cent of n-ribose. After 24 hours at 37” the cells were harvested in a Sharples supercentrifuge. About, 2 gm. of cells (wet weight) obtained from 1 liter of medium were ground in a mortar for 5 minutes at 0” with 6 gm. of alumina, and the paste was extracted with 15 ml. of 0.05 M 2-amino-2-(hydroxymethyl)-1, 3-propanediol buffer, pH 7.5 (Tris buffer). The clear extract obtained by centrifugation at 15,000 X g for 30 minutes (12 ml.) was treated with 2.4 ml. of 1.0 per cent protamine sulfate (salmine, Lilly) solution. The precipitate which formed was collected by centrifugation and homogenized in a Potter-Elvehjem homogenizer (24) with 6.0 ml. of 0.05 M K2HP04. The